Question

I need help on two questions on my chemistry homework

Answer 1

If 12.6 grams of iron (III) oxide reacts with 9.65 grams of carbon monoxide to produce 7.23 g of pure iron, what are the theoretical yield and percent yield of this reaction? Be sure to show the work that you did to solve this problem.

unbalanced equation: Fe2O3 + CO yields Fe + CO2

Answer 2

and I have another question

Answer 3

If 143 grams of chromium react with an excess of oxygen, as shown in the balanced chemical equation below, how many grams of chromium oxide can be formed? Please show all your work for the calculations for full credit.

4Cr + 3O2 yields 2Cr2O3

Answer 4

All stoichiometry problems are essentially the same. This is how to find the theoretical yield.

General Scheme:
\(\sf \large 1.\)First write and balance an equation for the process described.
\(\sf \large 2.\)Next, use the stoichiometric coefficients to find moles produced.
\(\sf \large 3.\) Set up a ratio using the species of interest, like so:

e.g. for a general reaction:

\(\sf \large \color{red}{a}A + \color{blue}{b}B \rightleftharpoons \color{green}{c}C\)

where upper case are the species (A,B,C), and lower case (a,b,c) are the coefficients ,

\(\sf \dfrac{n_A}{\color{red}{a}}=\dfrac{n_B}{\color{blue}{b}}=\dfrac{n_C}{\color{green}{c}}\)

From here you can isolate what you need.
For example: if you have 2 moles of B, how many moles of C can you produce?

solve algebraically: \(\sf\dfrac{2}{\color{blue}{b}}=\dfrac{n_C}{\color{green}{c}}\rightarrow n_C=\dfrac{2*\color{green}{c}}{\color{blue}{b}}\)


\(\sf \large 4.\) Solve


----

Then, Percent yield =\( \sf \dfrac{|theoretical-actual ~yield| }{theoretical }*100 \% \)

The "actual yield" is given in the question.

Answer 5

Can u help me solve them

Answer 6

I can tell you if you're doing it right or not, but you have to post your work in order for me to do that.

Answer 7

Im really confused and have turn in my homework soon

Answer 8

4 Cr + 3 O2 → 2 Cr2O3

(143 g Cr) / (51.99616 g Cr/mol) x (2 mol Cr2O3 / 4 mol Cr) x
(151.99061 g Cr2O3/mol) = 209 g Cr2O3

Answer 9

so you wanna do the second one? thats right (assuming you didn't make a mistake with the arithmetic)

Answer 10

for the second one im really confused

Answer 11

btw, i know you're copying and pasting, copied that from here
https://ca.answers.yahoo.com/question/index?qid=20130420150711AAXIf8o

Answer 12

you're not gonnna learn anything by doing that..

Answer 13

can u help me then

Answer 14

Is what i gave you initially (the scheme) not sufficient? What else do you need?

Answer 15

can u help me with at least the first onelike do i together

Answer 16

Okay you start

Answer 17

unbalanced is Fe2O3 + CO yields Fe + CO2

Answer 18

k now balance it

Answer 19

Fe2O3 + 3 CO = 2 Fe + 3 CO2

Answer 20

Awesome. Now we need to find the moles of each (and determine the limiting reactant - the one with least moles).

The formula is \(\sf moles=\dfrac{mass}{Molar~mass}\)

lets do iron(III) oxide first, the mass is 12.6 grams and the molar mass is 159.69 g/mol

Answer 21

ok

Answer 22

what did you get?